Strut bars arent what im talking about. I have them on my car, and they do work as i stated.

Think of your body. The body is the firewall, the arm is the fender. Now, strut bars would stiffen the elbow. Is there anymore movement? Sure there is, the shoulders. Fender braces keep the "shoulders" stiff.
Alot of cars/trucks dont have this issue like the 240 do.